We'll turn to the latest on the boston terror attack and that female dna we told you has been found on fragments of one of the bombs is raising big, new questions in the investigation. Abc's brian ross of course is here. Has all the de us. Goodorning. Good morning. With the discovery of the female dna on bomb fragments and developments overnight in russia fbi agents are widening their net looking for possible accomplices of the two brothers in the bombing and now there's a tight focus on one woman in particular. Officials say fbi agents want to obtain dna samples from catherine russell, the widow of the elder tsarnaev. Agents were seen leaving her home with a set of evidence bags. She was seen leaving with her attorneys who continue to insist she did not know about her husband's bomb plot. Two weeks after the bombing, the investigation continues to expand as people briefed on the case say the fbi reportedly now has almost a dozen individuals considered to be persons of interest. Some have -- may have been involved in helping build the bombs. Others may have been involved in helping radicalize the brothers. Reporter: Dzhokhar tsarnaev is no longer cooperating with the fbi and is now confined by himself to a tiny cell at this federal prison medical center outside boston getting a taste of what his life will be if convicted without being sentenced to death. He has no interaction with other inmates. It's not plush, it's nothing. Imagine if they put you in a room and locked you down and said, this is where you're going to live for the rest of your life. Reporter: Overnight there was also a new video obtained by "entertainment tonight" of the elder tsarnaev brother from his days as a boxer trying to make the u.S. Olympic team. It's the first time he's been heard speaking. Tamerlan tsarnaev. Authorities say the discovery of the female dna could be explained by that of it's a victim or someone who handled it innocently or somebody involved in making the device that killed three people and injured so many more, robin. Don't know at this point. All right, brian, thanks very much.

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